Cardiac arrest, also known as cardiopulmonary arrest or circulatory arrest, is a sudden stop in effective blood circulation due to the failure of the heart to contract effectively or at all. Cardiac arrest is often treated via attempts at resuscitation. However, due to the acuity of these situations, the patient's outcome depends greatly on the good decision making and the timing of his caretakers.
To improve the likelihood of success, caretakers often follow guidelines for decision making and timing of interventions. For example, the American Heart Association has created intervention guidelines called the Advanced Cardiac Life Support (ACLS) protocols. Many hospitals mandate that providers be trained in these life-saving protocols.